Tracer device for a rocket

ABSTRACT

A tracer device is provided for a rocket and comprises at least one sheath arranged at the rear of the rocket and containing a pyrotechnical charge whose combustion produces a flame enabling the rocket to be followed along its trajectory. The sheath terminates in a convergent-divergent nozzle and the axis of the sheath is inclined with respect to the longitudinal axis of the rocket so as to direct the flame into the region comprised between the inside boundary of the air stream flowing behind the rocket and the outer boundary of the propellent gas jet.

Unite States atent Bouisse et a1. Dec. 19, 1972 54] TRACER DEVICE FOR AROCKET 3,070,955 1/1963 Kallin et al. ..102/87 Inventors: Jean MarieGermain Bouisse, Cue 3,145,657 8/1964 Shrout ..102/87 Boisgelin; CharlesEtienne Georges OTHER PUBLICATIONS Martel; Franck Pierre Antoine Vilb of295-p Websters Third New international Dictionary 1965 de Bois, all ofFrance P 1359 [73] Assignee: Etat Francs Primary Examiner-Benjamin A.Borchelt [22] Filed: June 23, 1970 Assistant Examiner-H. J. Tudor pp NoI 49 054 Attorney-Waters, Roditi, Schwartz and Nissen ABSTRACT 30F'A1'tP"tD orelgn pp y am A tracer device is provided for a rocket andcomprises June 23, 1969 France "6920265 at lea t one heath arranged atthe rear of the rocket and containing a pyrotechnical charge whose com-U-S. Cl. bustle produces a flame enabling the rocket to be [5 ..F42bfollowed along its trajectory The heath terminates in [58] Field ofSearch ..102/87, 60, 66, 6, 90, 39, a convergem divergem nozzle and theaxis f the 102/493; 60/355 RS sheath is inclined with respect to thelongitudinal axis of the rocket so as to direct the flame into theregion [56] References C'ted comprised between the inside boundary ofthe air stream flowing th rocket and the outer b01111- dary of thepropellent gas jet. 2,829,596 4/1958 Loedding ..102/87 2,986,999 6/1961Fiedler et a1. ..102/87 10 Claims, 4 Drawing Figures PAFENTEU DEC 191972 TRACER nuvrcu son A ROCKET BRIEF SUMMARY OF THE INTENTION the bodyof the vehicle at the moment when they leave the body at the readthereof, the tracer device being located on the body. These eddies areparticularly violent above supersonic speeds. Moreover, wind velocityand direction also produce disturbing effects on the tracer flame whenthe velocity is subsonic.

Attempts have been made to remedy these'drawbacks. Thus, it is known toarrange deflectors on tracers, at the outlets thereof, so as to maintainthe apparent diameter of the flame appreciably constant or to lengthenthe vehicle with a cowling surrounding the flame so as to create a lessturbulent zone therearound.

An object of the present invention is to remedy the aforesaid drawbacksin a novel way.

According to the invention, the tracer device for a rocket or similarvehicle comprises at least one sheath arranged at the rear of the rocketand containing a pyrotechnical charge whose combustion produces a flameallowing the rocket to be followed along its trajectory and the tracerdevice is characterized in that the sheath terminates in a nozzle ofconvergent-divergent form, the centerline of the sheath being at anangle to the longitudinal axis of the rocket so as to direct the flameinto the region between the inner boundary of the air streams emergingbehind the rocket an the outer boundary of the propellant gas jet.

According to a preferred construction, the sheath is fitted at aninclination on one of the ends of a rotatable cylindrical block which isembedded at its other end in a housing extending parallel to thelongitudinal axis of the rocket.

Preferably the angle between the axis of the sheath and theaxis of thecylindrical block lies between 25 and 60.

The nozzle of the sheath allows the incandescent particles issuing fromthe combustion of the pyrotechnical charge to be given sufficientvelocity for them to cross the turbulent zone and reach the region wherethe flows of propellent gas and air run side-by-side, whereby there isproduced an extension of the flame. Proper guidance of the flame isobtained through the adjustment of the inclination of the sheath on thecylindrical block in conjunction with the adjustment of the latter inthe housing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 diagrammatically illustrates theaerodynamic phenomena occurring at the rear of a rocket equipped with atracer device according to the invention and moved under the effect of apropellent;

FIG. 2 shows partly broken away and in section two components of thetracer device;

FIG. 3 is a perspective view of one component of the device; and

FIG. 4 is an axial section of a sheath containing the pyrotechnic chargeinside the element of the device.

DETAILED DESCRIPTION Referring to FIG. 1 of the drawing therein is seenthe rear portion of a rocket F as shown in motion in the air. The rearportion of the rocket F is provided with stabilizing fins a. Apropellent gas jet b issues from a nozzle c at the rear of the rocketand the gas jet b expands progressively and approaches the air streamlayer d which travels along the body of rocket F. A space e is formedbetween the inner boundary f of the air stream layer d and the outerboundary g of jet b. In this space are produced vortices b particularlyat the rear face of rocket F.

According to the invention, rocket F carries at its rear a tracer devicefor emitting a flame 2, and this device comprises two elements 1 whichare embedded by means of a synthetic resin 3 in housings 4 arrangeddiametrically around nozzle 0 of rocket F.

Each element 1 is composed of a sheath 5 mounted perpendicularly at itsbase 6 at the center of a sloping surface 7 of a cylindrical block 8which is secured in housing 4. By this arrangement, the axis of sheath 5is offset by an angle i from the axis of the cylindrical block 8. Themagnitude of angle 1' is between 25 and At its free end, sheath 5terminates in a nozzle comprising a convergent portion 9 and a divergentportion 10.

Sheath 5 is a one-piece body and is lined internally with a polyesterresin layer 11 containing a refractory metal oxide. The sheath 5contains in its cylindrical portion a pyrotechnical charge 12, thecombustion of which gives rise to flame 2 emerging at the outlet of thedivergent portion 10.

In one preferred embodiment, the casing of sheath 5 is constituted ofmetal, graphite or a thermosetting molded plastic. The molded plasticmaterial is advantageously fabricated from a base of phenolic moldingpowder containing asbestos.

The internal lining of polyester resin 11 in sheath 5 containing therefractory charge insures the thermal safety of the jacket of thesheath. In a preferred form, the refractory metal oxide is magnesiumoxide. Other metallic oxides resistant to heat are suitable such aszirconium oxide and the like.

The tracer device produces flame 2 directed at an inclination withrespect to the longitudinal axis of rocket F toward the region where theair stream layer 0! and the gas jet b come together. This is achievedthrough adjusting the angle i of sheath 5 on block 8, the value of iresulting from a preadjustment of the position of block 8 around itsaxis before it is secured in the housing 4. In this respect block 8 maybe rotatably mounted in the housing and after suitable adjustment itbecomes embedded in resin 3. It is recalled that surface 7 of block 8 isa sloping surface, and therefore the angle i between the axis of thesheath 5 and the axis of the block 8 depends on the position of theblock 8 around its axis.

The discharge velocity of the incandescent particles in flame 2 isremarkably increased by the nozzle end of sheath 5, so that flame 2easily crosses the turbulence zone h and is, in a fashion, seized by theair and gas flows, the result of which is to lengthen flame 2.

It follows from this that the apparent diameter of the flame 2 as seenby an observer is appreciably increased and consequently the potency ofthe tracer device according to the invention is remarkably enhanced.

WHAT IS CLAIMED IS:

1. For a rocket having a rear portion with a propellent jet emittedtherefrom along the longitudinal axis of the rocket and which expandsrearwardly to approach an air stream layer around the rocket, a tracerdevice comprising means for producing a tracer flame at the rear portionof the rocket between the outer boundary of the propellent jet and theinner boundary of the air stream layer, said means comprising a sheathsupported in said rear portion of the rocket andhaving an outlet nozzle,the axis of said nozzle being outwardly inclined at a rearwardlydiverging angle with respect to the longitudinal axis of the rocket, andmeans in said sheath for generating said tracer flame.

2. A tracer device as claimed in claim 1 wherein said outlet nozzle is aconvergent-divergent nozzle.

3. A tracer device as claimed in claim 2 wherein the rear portion of therocket is provided with an opening constituting a housing and said meansfurther comprises a cylindrical block mounted in said housing andsupporting said sheath.

4. A tracer device as claimed in claim 3 wherein said cylindrical blockhas an axis extending parallel to said axis of the rocket and an outerface inclined with respect to said axis of the block.

5. A tracer device as claimed in claim 3 wherein said sheath has an axiswhich is inclined with respect to the axis of the block by an amountbetween 25 and 60.

6. A tracer device as claimed in claim 3 wherein said means furthercomprises a synthetic resin in said housing embedding said cylindricalblock therein.

7. A tracer device as claimed in claim 1 wherein said sheath isconstituted of one element of the group consisting of metal, graphiteand thermosetting plastic material.

8. A tracer device as claimed in claim 7 comprising asbestos in saidthermosetting plastic material.

1. For a rocket having a rear portion with a propellent jet emittedtherefrom along the longitudinal axis of the rocket and which expandsrearwardly to approach an air stream layer around the rocket, a tracerdevice comprising means for producing a tracer flame at the rear portionof the rocket between the outer boundary of the propellent jet and theinner boundary of the air stream layer, said means comprising a sheathsupported in said rear portion of the rocket and having an outletnozzle, the axis of said nozzle being outwardly inclined at a rearwardlydiverging angle with respect to the longitudinal axis of the rocket, andmeans in said sheath for generating said tracer flame.
 2. A tracerdevice as claimed in claim 1 wherein said outlet nozzle is aconvergent-divergent nozzle.
 3. A tracer device as claimed in claim 2wherein the rear portion of the rocket is provided with an openingconstituting a housing and said means further comprises a cylindricalblock mounted in said housing and supporting said sheath.
 4. A tracerdevice as claimed in claim 3 wherein said cylindrical block has an axisextending parallel to said axis of the rocket and an outer face inclinedwith respect to said axis of the block.
 5. A tracer device as claimed inclaim 3 wherein said sheath has an axis which is inclined with respectto the axis of the block by an amount between 25* and 60* .
 6. A tracerdevice as claimed in claim 3 wherein said means further comprises asynthetic resin in said housing embedding said cylindrical blocktherein.
 7. A tracer device as claimed in claim 1 wherein said sheath isconstituted of one element of the group consisting of metal, graphiteand thermosetting plastic material.
 8. A tracer device as claimed inclaim 7 comprising asbestos in said thermosetting plastic material.
 9. Atracer device as claimed in claim 1 wherein said sheath includes aninternal lining of a powdered refractory metallic oxide.
 10. A tracerdevice as claimed in claim 9 wherein said metallic oxide is magnesiumoxide.